3
DETERMINE TOTAL NUMBER OF HOLES TO BE REAMED, THEN LOCATE MOST COST EFFECTIVE REAMER ON MATERIAL
CONDITION/HARDNESS LINE

CHIPCLASS

MATERIALCLASS

MATERIALCONDITION/HARDNESS

TOTAL NUMBER OF HOLES TO BE REAMED

1

5

10

20

40

80

160

320

640

20

NON-FERROUS LONG CHIPS

SOFT - UNDER 10% SILICON

HSS

HSS

HSS

HSS

CT

CT

CT

CT

CT

ABRASIVE - OVER 10% SILICON

HSS

Cobalt

CT

CT

CT

CT

CT

CT

CT

40

NON-FERROUS SHORT CHIPS

SOFT - FREE MACHINING

HSS

HSS

HSS

HSS

CT

CT

CT

CT

CT

HARD - HIGH TENSILE

HSS

Cobalt

Cobalt

CT

CT

CT

CT

CT

CT

60

CAST IRONS

SOFT - 120 TO 220 Bhn

HSS

HSS

HSS

CT

CT

CT

CT

CT

CT

MEDIUM - 220 TO 300 Bhn

HSS

Cobalt

Cobalt

CT

CT

CT

CT

CT

CT

HARD - OVER 300 Bhn

HSS

Cobalt

CT

CT

CT

CT

CT

CT

CT

80

LOW STRENGTH STEELS

SOFT - 80 TO 175 Bhn

HSS

HSS

HSS

CT

CT

CT

CT

CT

CT

MEDIUM - 176 TO 275 Bhn

HSS

Cobalt

CT

CT

CT

CT

CT

CT

CT

HARD - OVER 275 Bhn

Cobalt

Cobalt

CT

CT

CT

CT

CT

CT

CT

100

MEDIUM STRENGTH STEELS

SOFT - 150 TO 275 Bhn

HSS

HSS

HSS

CT

CT

CT

CT

CT

CT

MEDIUM - 276 TO 425 Bhn

HSS

Cobalt

CT

CT

CT

CT

CT

CT

CT

HARD - OVER 45 Rc

Cobalt

CT

CT

CT

CT

CT

CT

CT

CT

120

HIGH STRENGTH STEELS

SOFT - 135 TO 275 Bhn

HSS

HSS

CT

CT

CT

CT

CT

CT

CT

MEDIUM - 276 TO 425 Bhn

Cobalt

Cobalt

CT

CT

CT

CT

CT

CT

CT

HARD - OVER 45 Rc

Cobalt

CT

CT

CT

CT

CT

CT

CT

CT

140

HIGH TEMPERATURE ALLOYS

ALL CONDITIONS

CT

CT

CT

CT

CT

CT

CT

CT

CT

CT=Carbide Tipped HSS= High Speed Steel

REAMER BASICS

The reamer is used to finish machine a previously formed hole to an exact diameter with a smooth finish. It should not be used to significantly enlarge a hole (max. 5% - depending on material and hardness).

Carbide tipped reamers are especially appropriate for close tolerance reaming. Because carbide is very highly resistant to wear, the reamer will produce accurate hole size and a smooth finish far longer than high speed steel or cobalt.

The reamer is an end cutting tool, cutting only on the chamfer's edge at the outside diameter of the preformed hole. The standard 45º chamfer angle provides effective cutting action for most materials.